Blow out Preventers are often closed and locked over night or for extended periods of time to shut in an oil or gas well. In the closed position, the ram shaft extends into the well bore where it is exposed to well fluids. Chemicals in the well fluids tend to deposit on the exposed portion of the ram shaft, forming an abrasive coating. This abrasive coating is rough, hard and difficult to remove. During normal operation the ram shaft is pulled back and forth past circumferential seals which seal around the ram shaft. As the abrasive coating is pulled back and forth through the seals engaging the ram shaft, the seals sustain damage leading to premature failure and a loss of containment of the well in the event of a blow out.